Video Transcript
If you're watching this, you're probably looking for a lower parts kit to finish your stripped AR-15 low receiver. Now there's a ton of lower parts kits out there and they all do about the same thing, but our lower parts kit, the T.REX ARMS Lower Parts Kit, is gonna offer you something a little bit different. Now this kit is obviously very small. It's a stripped lower parts kit, as in being this is just the guts of the lower receiver, so there's still quite a bit of parts you're gonna need to finish out your low receiver.
That was kind of the intent behind this. If you're someone like me, you're very particular in what you want with your gun, you don't wanna buy a lower parts kit that has a bunch of stuff in it and you're gonna have to end up changing those parts out. As we look at the back of the packaging, we have all of the parts in the lower parts kit listed out. So we have our safety, we have our magazine catch, the spring for the magazine release, the magazine button itself. We have our bolt catch, we have the plunger and the spring for the bolt catch and we have the roll pin for it. We have our buffer retainer, pin and spring. We have our two take down pins, our springs for each, detents for those and then we have our detent and spring for our safety. So we have all of the guts for our lower parts kit right there.
With this lower parts kit being just the guts of the lower receiver, we get to be a little bit more particular with the other parts that we wanna put into our lower that aren't included in this lower parts kit. So, obviously we need our lower receiver, we need a trigger guard. In this case, we're going with a BCM, one of the ones that we sell on the website. We have just an A2 grip that I've put some skater tape on. Geissele trigger, I think this is essential for every lower, at least every lower I'm using. BAD Lever, if you're into that, I really like BAD Lever's. And then I want an A5 buffer system, so that's what I got going on here. So I've got a B5 stock, VLTOR A5 buffer tube with a BCM end plate, castle nut. And then we have a green spring coat, rifle length spring with an A5H tube buffer weight. So that's all the parts we got. Let's go ahead and install this guy up.
There are a lot of different ways that you can install these parts. And the way I like to do it is I just like to go from the front of the receiver down to the back. So I'm going to start with the front takedown pin. And I'm actually going to use this with minimal tools, nothing fancy. So I'm going to just act like I don't have a bunch of fancy armor tools specific to the AR-15 platform. I'm going to take the detent and grab some needle nose pliers that have some good grip on them. I'm going to use them to get this detent started. Now I'm going to take the pivot pin and just push it the rest of the way down. You hear it click. I'm going to go in just like that. I found that to be one of the easiest ways to put this pivot pin in. This is generally the hardest part of the lower receiver to install. We're going to go ahead and do the magazine release magazine button next. Pretty simple. Let's drop this guy in there. Drop the spring in.
Take your button. You can generally get this started with just your fingers. I highly recommend doing that. We got it started. You can take a pen or really anything and push the magazine button through and then just continue to tighten this guy up. You will know you've threaded this on far enough is the magazine catch won't be protruding through the button and you won't have any exposed female threads. So you can adjust this by going one thread deeper or one thread less. If you want the button to be less exposed or more exposed, it won't really affect all that much. So now we're going to do the bolt catch and we're going to start the receiver back to where it was. Again, there's a lot of different ways you can do this, but I'm actually going to start this in a similar fashion comparatively to the front pin and pin taking my needle nose pliers, getting that roll pin secured in there. And all I want to do is get this guy started. So I can literally just start this with the hammer directly.
Now that it's started and I just don't need my pliers anymore, I can get it going just a little bit more with a fatter punch. Just like that. And then I can go ahead and take this little guy right here. Looks like we're going to call it a plunger. And there's a spring that fits over it perfectly. Now if you have a lower parts kit that includes a fire control group, this spring is very similar to the spring that goes under the disconnect on your trigger. If you do mix them up, it will work, but you're just probably going to have some trigger issues later on. Go ahead and push that guy through the hole.
Pop that in there just like this now. There's a little bit of a technique to do this. So I'm going to use my ring finger, take my thumb and index finger to hold the punch. Just tap it on in. And sometimes, like this, if you slightly miss it, this will be kind of stuck. That's OK. Just wiggle it around and it will catch in there right where it needs to go. So now the roll pin has actually captured the bolt catch and then we can just finish it off. Once it's about as low as it can go with that fat punch, if I keep hitting it with a fast punch, I'll get some marring on the lower receiver. So I'm going to go to a smaller punch. Actually, I'm going with this one just to finish it off and get that roll pin nice and flush just like that. So like I said, we're going to go front to back again. There's not really-- I'm sure there is a specific order that's recommended, but this is just what I do. Go ahead and drop the trigger in there, in this case, the Geissele trigger. There we go.
Once we've got the bottom half of the trigger in, we're going to do the trigger hammer. There's a little trick to this. What I'm going to do is I'm going to lay the springs down, pivot the trigger. I'm actually going to pull it back so it catches on the disconnect. You'll hear it click, and it's in there. So generally, this is one of the more difficult things to install for people. But if you pull that trigger back, it will click in place. Just be careful you don't hit the trigger, because it will fly out. Now, I'll take the other trigger pin, and I'm going to control this just so it doesn't fly out. And all I got to do is push the front of this trigger hammer down, and then this guy, this slide on through.
Just like so. All right. We can function check the trigger now. All good to go. Now, depending on the kind of trigger guard you have, it may vary on how you install this. This is just the BCM collar one that we sell. So with no screws or roll pin in there, we're just going to drop it onto the lower receiver. And then the front of the trigger guard is actually a threaded screw. So we'll just go ahead and screw that guy in.
Now we're going to do the most dangerous part of the lower receiver, and that is the roll pin for the trigger guard on the back of the lower receiver. So if you start tapping this roll pin in these leaves on the lower receiver are not supported, they can break off, and in fact, they probably will. So just be very careful. You can use a bench block, you can use something. It doesn't necessarily have to be a bench block. Just make sure that they are supported. I like the bench block because there's a bunch of holes here, and I can just go ahead and tap that in just like that, and it's nice and supported. Nothing fancy here. I'm literally just going to use my fingers to get it started. Make sure it's supported. So as I'm tapping it, I'm ensuring that both sides of these leaves are touching the bench block.
And then I'll just want to flush this guy out. This bench block is not the most ideal candidate for this sort of job because the lower receiver is not all that well balanced, but make it work. Make sure that roll pin is slightly past the leaf on both sides. We don't want it sticking out either side, but honestly, if it is flush on one side, that'll be fine. Sure, you guys aren't going to fall out. Now we're going to install the unique part about this low receiver, and that is the safety. So what I like to do is actually flip this guy upside down.
Go ahead and put my safety in. And I can just drop the safety detent in. This is the one that's very pointy. It's larger than the other two that are in the kit. Just hold right down in there. Now the difference between the springs for the pivot pins and the safety, you can tell is the length. You'll have two that are long and skinny, and then you have a shorter one that's a little bit fatter. That's going to be your safety. Also, the shorter fatter one won't fit in the holes for the pivot pins, takedown pins. So got the pin in there. I can literally just put the safety there, use my grip to guide it, and just put her on there and you're good to go. So this screw can get a little bit annoying to install in here, kind of just kind of Finessing in there. The flatheads are much more annoying than the Allen key ones. The Allen key ones, you can actually just stick on it until it'll stick to it, and then you can get in there. This one, you kind of gotta use your fingers.
If you are wondering how tight you need to go on this screw, first off, if you're screwing it in, you feel any sort of resistance, you're probably cross threading, back out and start over. If you do start to cross thread it too far, most lower receivers can thread this way as well through the trigger guard, or through your, where your trigger is, take the trigger out, thread the screw the other way, and it'll retract the threads. But once you get it on there, once you meet the resistance after it goes all the way in, just give it like another quarter to have a turn, and you'll be fine.
Now, we get to install the ambi part of the safety. So this is what the safety will look like if you don't want the ambi on there. You'll just have an empty screw hole. Totally fine, it is completely slick. There's no catch there. So again, if you don't want the ambi, you can just take it off and leave it that way. But if you do want the ambi, slide it on there, screw in, you can add Loctite if you want. I've never put Loctite on these, they've never come off. You can actually torque these on pretty good. So that's exactly what we're gonna do. Just like that.
The reason why I like ambi safeties is obviously flick the fire with your thumb, and I can go back to safe without breaking my grip. And as you can see, the safety is very, very clicky on either side. With the rear takedown pin, you want the grooves to be orientated back towards the back of the lower receiver. Your slider in there just like that. Take your detent, slide it in that little hole there. What I like to do is I take the spring, just push it in there, make sure it's actually caught. And then I take this back out. Now you can take your buffer retaining pin and drop it in there for now, which is fine. You just let it sit there. Now we're gonna take our buffer tube.
I recommend putting the stock on the buffer tube now. It just makes threading it on a little bit easier. Go ahead and thread your castle nut all the way on as far as it'll go. Slide your end plate on as well as far as it'll go. And then all you're doing is threading this guy on. So I'm gonna thread this until I start to hit that buffer retaining pin. Once I hit it, I need to push the buffer retaining pin down, give it one more turn, and that's as far as it needs to go.
Now we still have to put the takedown pin spring in, so the buffer tube's threaded all the way on, and obviously this spring can't get in there, so all I'm gonna do is I'm gonna turn the buffer tube slightly so I can fit this guy in there. Once it goes in there, now all I'm gonna do is use something, I just use my thumbnail to push the spring in so I can turn the buffer tube back. And the key here is making sure that spring is straight, so when I push the end plate down, the spring doesn't get bent underneath this end plate.
And once that's on there, I'm gonna just use my fingers to thread the castle nut on. There you have it. Gotta torque that down and stake it. As we torque down this castle nut onto the lower receiver the stocks gonna want to rotate So we just want to make sure we have something keeping this stock straight So as we tighten it you don't have a crooked stock on your on your lower So the way I like to do this is I'm actually going to take the tool whatever the tool we're using is To tighten down the castle nut. This is just the BCM tool And I'm actually not going to attach it to anything. I'm just gonna use my fingers here, and I'm going to just keep an eye on the stock in regards to the pistol grip and just make sure that as I slightly tighten this that nothing is rotating. So I'm just gonna go as tight as I can with my hands and call that good for now.
Now I'll get my breaker bar or you can use a torque wrench and go to the specified torque spec I'm just gonna crank on it. I'm gonna put my upper body into this lean into the to the buffer tube So I won't rotate and give it a little ugga-dugga and she'll be good to go. She is nice and straight. Now for staking it you're going to need an actual stake punch And I the way I like to do this there's people that are really good at sticking and they take a lot of pride in their stakes I'm not one of those people. This is just an AR-15 low receiver. But what I like to do is just make sure she's centered up Give it a little tap to get it started That's a little bit closer to the edge than I would want so I'm going to redirect the stick towards the lower So whichever direction you want this hole to go just point your stake towards it or in the opposite direction.
Just like that. So we got it pushed back a little bit now I can stake down and this should be a good looking stake That is beautiful as one of the best takes I've ever had. Now that we got that guy's steak down there go ahead and throw your buffer and buffer spring in there should just slide right in and then if you have a bad lover go ahead and throw that guy on. There you have it guys That is the T.REX ARMS Lower Parts Kit how to install it if you guys have any questions regarding the Lower Parts Kit, how to install it anything at all to go ahead and email us a [email protected].